This invention relates to novel tetracyclines and to processes for their production and use.
Carbocyclic tetracyclines have been prepared by total synthesis (cf., f.e., German Offenlegungsschrift 1,543,221). No heterocyclic tetracycline analogues (wherein a carbon atom of the tetracyclic system is replaced by a hetero atom, f.e. O or S) is known thus far.